1. Field of the Invention
The present invention is directed to a lined plug valve, and improved means for sealing the valve against leakage. A sealant is introduced into the chamber defined by the bottom of the liner, the bottom of the plug and the body member, providing forces which continuously urge the plug toward and in sealing relationship with a diaphragm at the top of the body member, ensuring against external leakage thereof.
2. Description of the Prior Art
The subject invention comprises an improvement over the lined plug valve of my U.S. Pat. No. 3,521,856, assigned to the assignee of this application.
The valve of the subject invention differs from the valve of U.S. Pat. No. 3,521,856 in that the sealant surrounding the upper end of the valving member of said patent is disposed in open communication with sealant disposed in a chamber adjacent the lower end of the valving member, and wherein the cross-sectional area of the lower end of the valving member is greater than the cross-sectional area of those portions of the upper end of the valving member which are subjected to sealant.